BMW Repair: BMW Audible Alarm Wont Stop, service tomorrow, audible alarm

Question
When I started my wife's 1993 Z4 last night, the audible alarm (like the keys are in the ignition) would not stop. Closed/Opened all doors, hood and trunk; put roof down/up; used key fob to lock/unlock doors - the alarm kept going.

The only thing I noticed was that when I started the car, a message briefly displayed:

"Service -1250 mi"

We drove the car home (30 minutes) - would that cause the alarm to stay on the entire time?  The alarm turned off after I turned the car off for 5 minutes.  I plan to take it for service tomorrow (Monday).

Thanks

Answer
Jim, Z4 was introduced in 2003. What is a 1993 Z4?
Is this the vehicle Alarm (DMW) siren that goes off? Or the gong like the door is open with the key in the ignition? If it is the gong staying on it is likely a intermittently faulty door lock actuator or a hood or trunk switch.
-Evan